Image processing apparatus and image processing method

ABSTRACT

An image processing apparatus and an image processing method for improving the productivity of image reading. Moving speed control processing performed by a control unit causes an image reading portion to move the position of a reading line in a sub-scanning direction of a document, to read an image on the document in the main scanning direction, and to output the image data on the read line. A read image correction portion converts (including primary resolution conversion processing of converting the resolution of the image data in the main scanning direction or sub-scanning direction into a specified resolution) the characteristics of the image data to data characteristics that are predetermined at the time of accumulation of the image data, and accumulates the converted image data in a HDD. Then, an image processing portion converts (including secondary resolution conversion processing of converting the resolution of the image data in the main scanning direction or sub-scanning direction into a specified resolution) the characteristics of the image data accumulated in the HDD into device characteristics of a device to which the image data is output, and outputs the converted image data to an image writing portion or to the device to which the image data is output, via an external I/F control unit.

PRIORITY STATEMENT

This application claims benefit of priority under 35 U.S.C. § 119 fromJapanese Patent Application No. 2006-306841 filed on Nov. 13, 2006, inthe Japanese Patent Office, the disclosure of which is incorporatedherein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus such as acomputer, a copying machine, a scanner, a printer, a facsimile device,and a complex machine thereof, and to an image processing method.

2. Description of the Related Art

Due to the developments of line sensor reading devices constituted byCCD units or writing devices using laser beams, copying machines aremaking the transition from analog to digital copying machines in whichdigitalized image data are processed. Such digital copying machines cameto be called “digital complex machines (MFP)” since these machines areequipped with a variety of functions such as a copy function but also ascanner function, a printer function, and a facsimile function toperform multifunction control (see, for example, Japanese UnexaminedPatent Publication No. 2001-223828).

An MFP is connected to a network and saves output data obtained fromeach function into a storage device such as an HDD provided within thedevice, so that the output data can be transmitted to and received fromthe outside through the network (see, for example, Japanese UnexaminedPatent Publication No. 2001-251522).

The MFPs used in an office have been diversified. For example, a smallMFP is installed next to a personal computer (PC) so as to be pairedwith the PC, and a worker using the PC can readily use the copyfunction, the scanner function, the printer function and the facsimilefunction thereof. Also, a medium-sized MFP is shared by a group ofpeople in a department or a division, and a certain level ofproductivity of the MFP, a sort function, a punch function, a staplefunction and the like of the MFP can be used. Furthermore, a large MFPis used in a department providing copy-related services in a company, ora company conducting a copy-related business itself, and is capable ofproviding high productivity and high-quality multiple functions.

As described above, the MFPs that are classified into a wide range ofclasses from a small size class to a large size class as described abovehave the functions that can be shared in each class, thus strong demandsare expected for some of the functions in each class. For example, inthe large MFP, post-processing is requested to be performed on papersobtained after the punching, stapling, folding or other plottingprocessing, or electronic filing is requested to be performedsimultaneously with copying, while in the small MFP an excellentinternet FAX function or PC-FAX function and, for personal use, afunction to printing a high-quality image on a special paper arerequired.

In recent years, the importance of information value in businesses hasbeen recognized, thus it is required that the information is sentpromptly, accurately, securely, clearly and effectively. With newfunctions for effectively handling information that uses digital datahas been provided because of the increase in speed of the communicationtechnology, spread of the communication technology, increase in thevolume of memories, reduction of the costs and size of the memories, andtechnical advantages in PCs, hence there is a demand for a new functionand integration thereof into the MFPs that handle digital image data asa part of digital data.

Here, an output in the MFP means, as described above, an output to paperin the copy function, and transmission using electronic data in thescanner function or facsimile function. The output form when performingtransmission using electronic data varies according to application. Forexample, when transmitting using a facsimile function, monochrome binaryimage data is transmitted, while when transmitting using a scannerfunction, for example, color RGB image data is transmitted.

In this manner, the MFP outputs image data using various functions, andoutput means of these functions have different output characteristics.For example, when outputting a paper, the characteristics of a writingunit are provided, and when performing scanner distribution, thecharacteristics of a display are provided.

Moreover, an output at a resolution determined in each output device, oran output at a resolution desired by an operator is requested. Forexample, a plotter is requested to output at a resolution of 600 dpi,while scanner distribution or a facsimile is requested to output at aresolution of 200 dpi.

However, a line sensor installed in a scanner unit or the like performsreading at a predetermined resolution, and needs to performmagnification processing on the read image data to obtain a desiredresolution for output (see, for example, Japanese Unexamined PatentPublication H6-054176).

However, as described above, when using a line sensor installed in ascanner unit to perform reading at a predetermined resolution andperforming magnification processing on the read image data to obtain adesired resolution for output, the original document had to be read outagain if the resolution of image data to be output.

In order to avoid such duplication of the work, when performing readingat a fixed resolution, accumulating the image data, and thereafterchanging the resolution of the accumulated image data, another problemarises in productivity when performing such single operation.

Technologies relating to the present invention are also disclosed in,e.g., Japanese Unexamined Patent Publication No. 2005-117290, JapanesePatent Application No. 3285941, and Japanese Patent Application No.3647347.

SUMMARY OF THE INVENTION

The present invention was contrived in view of the abovementionedpoints, and it is an object of the present invention to improve theproductivity of image reading.

In an aspect of the present invention, an image processing imageprocessing apparatus comprises a reading device for moving the positionof a reading line in a sub-scanning direction of a document to read animage in a main scanning direction of the document and then to outputimage data on the read reading line; a moving speed control device forvariably controlling a speed of the reading device moving in thesub-scanning direction of the document so that a resolution of the imagedata in the sub-scanning direction becomes a specified resolution; afirst conversion device for converting characteristics of the image dataoutput from the reading device into data characteristics predeterminedat the time of accumulation of the image data; an accumulation devicefor accumulating the image data converted by the first conversiondevice; a second conversion device for converting the characteristics ofthe image data accumulated by the accumulation device into devicecharacteristics of a device to which the image data is output; and anoutput device for outputting the image data converted by the secondconversion device to the device to which the image data is output. Thefirst conversion device is provided with primary resolution conversiondevice for converting the resolution of the image data in the mainscanning direction or the sub-scanning direction into the specifiedresolution, and the second conversion device is provided with secondaryresolution conversion device for converting the resolution of the imagedata in the main scanning direction or the sub-scanning direction intothe specified resolution.

In another aspect of the present invention, an image processing methodcomprises a reading step of moving the position of a reading line in asub-scanning direction of a document to read an image in a main scanningdirection of the document and then to output image data on the readreading line; a moving speed control step of variably controlling aspeed of moving in the sub-scanning direction of the document so that aresolution of the image data in the sub-scanning direction becomes aspecified resolution in the reading step; a first conversion step ofconverting characteristics of the image data output in the reading stepinto data characteristics predetermined at the time of accumulation ofthe image data; an accumulation step of accumulating the image dataconverted in the first conversion step; a second conversion step ofconverting the characteristics of the image data accumulated in theaccumulation step into device characteristics of a device to which theimage data is output; and an output step of outputting the image dataconverted in the second conversion step to the device to which the imagedata is output. The first conversion step is provided with a primaryresolution conversion step of converting the resolution of the imagedata in the main scanning direction or the sub-scanning direction intothe specified resolution, and the second conversion step is providedwith a secondary resolution conversion step of converting the resolutionof the image data in the main scanning direction or the sub-scanningdirection into the specified resolution.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription taken with the accompanying drawings in which:

FIG. 1 is a block diagram showing the configuration of functions of adigital copying machine of an embodiment of the present invention;

FIG. 2 is a block diagram showing the internal configuration of a readimage correction portion of the digital copying machine;

FIG. 3 is a block diagram showing the internal configuration of an imageprocessing portion of the digital copying machine;

FIG. 4 is a flowchart showing processing in which the digital copyingmachine transfers JPEG image data of RGB format that has a resolution of300 dpi to a PC through a network;

FIG. 5 is a flowchart showing processing in which the digital copyingmachine transmits binary image data having a resolution of 200 dpi bymeans of a facsimile; and

FIG. 6 is a flowchart showing processing in which the digital copyingmachine prints out read image data and distributes it to an external PC.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail withreference to the drawings.

FIG. 1 shows the configuration of functions of a digital copying machineof an embodiment of the present invention. This digital copying machine1 is a complex machine (MFP) equipped with a copy function, a scannerfunction, a printer function, and a facsimile function, is connected toa computer (PC) 2 via a communication wire 23 or a network, and isconnected via a communication line 24 so as to be able to performfacsimile communication (facsimile transmission/reception) via acommunication network including a public line network.

The inside of the digital copying machine 1 is configured by an imagereading portion 10, a read image correction portion 11, an imageprocessing portion 12, an image writing portion 13, an image dataexpansion bus control unit 14, an external interface (I/F) control unit15, a memory 16, a hard disk device 17, a network interface card (NIC)18, a facsimile control unit (FAX portion) 19, an operation displayportion 20, and an image data expansion bus 22. The PC 2, image writingportion 13, HDD 17, FAX portion 19 and operation display portion 20 arethe devices to which image data is output.

The image reading portion 10 functions as the scanner function, readingmeans, and moving speed control means. The read image correction portion11 functions as first conversion means and primary resolution conversionmeans. The HDD 17 functions as accumulation means. The image processingportion 12 functions as second conversion means and secondary resolutionconversion means. The image processing portion 12 and external I/Fcontrol unit 15 function as output means. A control unit 21 functions ascontrol means. The image reading portion 10 and image writing portion 13function as the copy function. The image writing portion 13 functions asthe printer function. The FAX portion 19 functions as the facsimilefunction. The control unit 21 and the like execute processing of eachstep.

Next, the detail of a series of processing from reading a document toprinting and outputting the document when copying the document of thedigital copying machine 1 is described.

First, the process from reading the document to outputting it onto apaper is described.

The image reading portion 10 has a line sensor configured by a CCDphotoelectric conversion device, an A/D converter, and a drive circuitfor driving these devices (illustration and detailed description ofthese devices are omitted since they are known devices). The imagereading portion 10 also has an optical unit configured by a light sourceand a mirror (illustration and detailed description of this device isomitted since it is a known device), wherein the optical unit is causedto move on the position of a reading line in a sub-scanning direction ofthe document that is set on a reading position (on a contact glass, forexample) by a user, to thereby read an image in a main scanningdirection of the document and then output the read image data on thereading line.

When the speed of moving the optical unit in the sub-scanning directionof the document is made faster than a normal speed, the number ofreading lines of the image data is reduced, whereby the resolution ofthe image data in the sub-scanning direction can be reduced to aspecified resolution (reduction).

Furthermore, when the speed of moving the optical unit in thesub-scanning direction of the document is made slower than the normalspeed, the number of reading lines of the image data is increased,whereby the resolution of the image data in the sub-scanning directioncan be increased to a specified resolution (enlargement).

At this moment, if the optical unit is a color CCD, each of red (R),green (G) and blue (B) color resolving light beams is subjectedphotoelectric conversion to amplify it, and thus obtained each RGB colorof 8-bit (may not be eight bits) red, green and blue electric imagesignals are sent to the read image correction portion 11 as the imagedata.

It should be noted that the document to be read is set in a readingposition of the image reading portion 10 by the user, or documents on adocument table are automatically fed one-by-one b an automatic documentfeeding device (ADF), not shown, and then set on the reading position,or alternatively the document to be read is simply caused to passthrough the reading position by the ADF.

By variably controlling the speed of the document passing through thereading position, the resolution of the read image data can be increasedor decreased as described above.

Furthermore, in the above explanation, the image data that is read bythe image reading portion 10 has eight bits in each color, but thenumber of bits is not limited to this value.

The image data read by the image reading portion 10 is output to theread image correction portion 11. The read image correction portion 11performs first conversion processing of converting the image data to adata characteristic that is determined beforehand when accumulatingimage data.

The first conversion processing performed by the read image correctionportion 11 is described in detail using FIG. 2.

First, the image data that is input to the read image correction portion11 is sent to an image region separation processing portion 30 and ascanner γ processing portion 31. The image region separation processingportion 30 extracts a distinctive area of the document on the basis ofthe image data. For example, extraction of an area having dot portionsformed by performing regular printing, extraction of an edge portionsuch as characters, determination on whether the image data is chromaticor achromatic, determination on whether a background image is white ornot, and other processing are formed, and the results of extraction anddetermination (image region separation data) are output to a filterprocessing portion 32.

On the other hand, the scanner γ processing portion 31 performs image γconversion to convert a γ characteristic of the image reading portion 10to a characteristic to be output, and then outputs thus obtainedcharacteristic to the filter processing portion 32. The filterprocessing portion 32 performs processing of converting spatialfrequency of the image data sent from the scanner γ processing portion31. Also, the filter processing portion 32 uses the image regionseparation data obtained from the image region separation processingportion 30, to perform distinctive filter processing on each of theextracted areas of the image data. For example, in the area in which dotportions are extracted, smoothing processing of smoothing an imagehaving dots. In the area in which edge portions are extracted, if it isdetermined that the image within the extracted area has a whitebackground, then the image within the extracted area is assumed to be acharacter portion, and thereby edge emphasizing processing of improvingMTF characteristics is performed.

In this manner, the image data processed by the filter processingportion 32 is output to a color conversion processing portion 33. Thecolor conversion processing portion 33 has a function capable ofsubjecting the image data to color conversion processing appropriate foran output characteristic. Since image formation for once accumulatingimage data is performed in this embodiment, in such a case the colorconversion processing portion 33 performs RGB conversion on general RGBdata or a predetermined space and outputs thus obtained data to aprimary resolution conversion processing portion 34. Then, the primaryresolution conversion processing portion 34 converts the resolution ofthe image data to a resolution appropriate for a subsequent device towhich the image data is output, and outputs thus obtained resolution toa compression processing portion 35. Specifically, primary resolutionconversion processing of converting the resolution of the image data inthe main scanning direction or sub-scanning direction into a specifiedresolution is performed.

For example, when an image on the document is read at a resolution of600 dpi in the main scanning direction and at a resolution of 300 dpi inthe sub-scanning direction, and the data of this image needs to beoutput at a resolution of 300×300 dpi, the resolution of the image issubjected to conversion processing by the primary resolution conversionprocessing portion 34 to obtain a desired resolution, and is thenoutput. At this moment the conversion processing may be performed usingknown computation processing including three-dimensional convolution.Thereafter, by the compression processing portion 35, the image datawhich is an output obtained after color conversion processing and theimage region separation data of the image region separation processingportion 30 are subjected to compression processing and then output tothe image data expansion bus control unit 14 via the image dataexpansion bus 22.

At this moment, for the image data, an irreversible compressionprocessing method including JPEG may be used, and, for the image regionseparation data obtained through image region separation processing, areversible compression processing method needs to be used because thedata relies on the positions of pixels.

The image data expansion bus control unit 14 once accumulates the imagedata and image region separation data received from the read imagecorrection portion 11 into the HDD 17 via the memory 16.

It should be noted that the compression processing methods to be usedare different for the image data and the data obtained as a result ofextraction and determination, thus these data may be accumulated afterbeing subjected to compression processing separately, but it isnecessary to control and manage the dependence relationship of thesedata and handle these data together in subsequent processing.

Furthermore, the data may be once accumulated in the HDD 17 as long asthe image data can be constantly sent to the image writing portion 13including the plotter at the same timing while images are continuouslyread by the image reading portion 10. However, actually the image datais only input and cannot be output during output preparation, thus thevolume of the image data might exceed the limited capacity of the memory16. Sufficient capacity of the memory 16 is required, but it simplyleads to the increase of costs of the hard drive. Therefore, the dataare once accumulated in the HDD 17, which is a large capacity storagedevice, so that exceeding the memory capacity can be prevented.

Next is described second conversion processing that is performed by theimage processing portion 12 to convert the characteristic of the imagedata into a device characteristic of a device to which the image data isoutput.

After accumulating in the HDD 17, the image data and image regionseparation data are transmitted to the image processing portion 12 viathe memory 16, and the image processing portion 12 converts thecharacteristic of the image data accumulated in the HDD 17 into an imagewrite characteristic for outputting a paper, e.g., a CMYK imagecharacteristic if the image writing portion 13 is a color writingdevice.

The detail of this processing is described using FIG. 3.

The data to be input to the image processing portion 12 includes theimage data and the image region separation data. First, an extensionprocessing portion 40 extends the image data and image region separationdata that are compressed by the compression processing portion 35 of theread image correction portion 11. Then, a filter processing portion 41performs filter processing on the image data in accordance with an MTFcharacteristic of the image writing portion 13.

In the abovementioned filter processing performed by the filterprocessing portion 32 of the read image correction portion 11, thecharacteristics of the data are corrected to predetermined datacharacteristics in order to be accumulated in the memory 16 or HDD 17,but in this case the filter processing portion 41 converts thepredetermined data characteristics (accumulated image characteristics)to the data characteristic (image characteristic) of the image writingportion 13.

Moreover, distinctive conversion is performed using distinctive imageregion separation data of the document.

After processing is performed by the filter processing portion 41, theimage data is sent to a color conversion processing portion 42. Thiscolor conversion processing portion 42 also uses the image separationdata of the image separation processing portion 30 to, for example,assume that the letters of the image region separation data are black ifthe image data is achromatic, and to perform black single colorprocessing when performing CMYK conversion based on the black letters.

The image signal processed by the color conversion processing portion 42is subjected to arbitrary resolution conversion processing by asecondary resolution conversion processing portion 43 and thereaftersent to a γ processing portion 44, and then γ conversion for convertinga predetermined accumulated image characteristic into an outputcharacteristic. Specifically, secondary resolution conversion processingof converting the resolution of the image data in the main scanningdirection or sub-scanning direction into a specified resolution isperformed.

Furthermore, a halftone processing portion 45 uses the image dataprocessed by the γ processing portion 44 to perform gradation processingin accordance with the characteristic of the image writing portion 13.For example, dither processing or error diffusion processing isperformed. Also, converting the density of the gradation of the imagewriting portion 13 (number of bits) is also performed here. For example,when outputting 1-bit data, an input 8-bit signal is subjected to ditherprocessing and made into 1-bit data.

In this manner, the image data processed by the image processing portion12 is once input to the image writing portion 13 via the memory 16 andHDD 17 again. When digital image data composed of CMYK is received, theimage corresponding to the image data that is received on a transfersheet is printed out by means of an electrophotographic process using alaser beam.

Here, the data are transferred via the image data expansion bus 22 toeach of the parts such as the read image correction portion 11, imageprocessing portion 12 and image writing portion 13, whereby input andoutput are performed. At this moment, even if, for example, the imagedata processed by the image processing portion 12 is output by the imagewriting portion 13, paper output may not be prepared depending on thecondition of the engine plotter in accordance with the timing at whichthe input and output are controlled. In such a case, the image data isonce kept in the memory 16 or HDD 17. Also, the image data expansion bus22 is shared by several modules and thus is controlled by the image dataexpansion bus control unit 14 adjusting the input and output.

Here, the abovementioned storage devices are connected to the image dataexpansion bus control unit 14, and RAMs such as the memory 16 and HDD 17that are storage media are connected. In the memory 16, when the dataare actually read by a line scanner of the image reading portion 10 andtransferred to the image processing portion 12, the image data is keptin the memory 16 at a transfer speed and at the time of processingperformed when, for example, reading is performed by the image readingportion 10 and when another processing is performed by the imageprocessing portion 12. Thereafter, the image data is stored into the HDD17 and used when reusing data, according to need.

The above has described the processing performed only for paper output,but the processing is performed when accumulating image data obtained byreading the document.

Next is described processing performed when the image data areaccumulated without depending on the devices and then reused.

First, processing in which an image on the document is read and thusobtained image data is accumulated without depending on the devices isdescribed.

The image reading portion 10 moves the position of the reading line inthe sub-scanning direction of the document set on the contact glass orADF, to read an image in the main scanning direction of the document,and outputs thus obtained image data on the read reading line to theread image correction portion 11. When reading the image using the imagereading portion 10, the control unit 21 performs moving speed control onthe image reading portion 10 so as to variably control the speed ofoptical unit moving on the document such that the moving speed of thedocument in its sub-scanning direction is made faster or slower thanwhen normal reading is performed so that the resolution of the imagedata in the sub-scanning direction becomes a specified resolution.

The read image correction portion 11 performs the first conversionprocessing of converting the characteristics of the image data that isinput from the image reading portion 10 into data characteristics thatare determined beforehand at the time of accumulation. Specifically, theimage data is converted into image data that does not depend on thedevices. Examples of the data characteristics of the image data thatdoes not depend on the devices include a color space such as sYCC,AdobeRGB space, and an RGB space that is commonly defined beforehand asequipment. Spatial frequencies are also defined, and the image datacharacteristics are converted to such data characteristics. Then, theimage data expansion bus control unit 14 stores and accumulates theimage data obtained after data characteristic conversion, into the HDD17 via the memory 16.

Next is described processing of outputting the read image onto a paperby using the image data accumulated in the HDD 17.

The image data expansion bus control unit 14 reads out the image dataaccumulated in the HDD 17, once stores it in the memory 16, and outputsit to the image processing portion 12. The image processing portion 12converts the input image data into device characteristics of a device towhich the image data is input. Here, the conversion is targeted forprint output performed by the image writing portion 13, thus the imagedata having data characteristics, which does not depend on the devices,is converted into image data having data characteristic corresponding tothe characteristics of the image writing portion 13, and is then outputto the image data expansion bus control unit 14. The image dataexpansion bus control unit 14 once stores the input image data in thememory 16 and then output to the image writing portion 13 which is thedevice to which the image device is input, whereby the image writingportion 13 prints out and outputs the image data onto a paper.

Next is described control processing performed when reducing the timefor scanning the document placed on the document table in the digitalcopying machine 1.

When increasing the speed of reading the image on the document, thecontrol unit 21 executes moving speed control processing on the imagereading portion 10, and the image reading portion 10 reduces the numberof lines reading the image data, whereby the speed of the documentmoving in the sub-scanning direction is made faster than a normal speedsuch that the resolution of the image data in the sub-scanning directionis reduced to the specified resolution. The time per unit time withrespect to one main scanning line is constant, and the read resolutionin the sub-scanning direction is reduced, whereby the number of readinglines is reduced. As a result, the time for reading one document isreduced.

In this manner, the speed of reading in the sub-scanning direction isincreased to reduce the reading time such that the image reading portion10 can read the image data at a resolution required to perform output.Then, the control unit 21 performs control and thereby causes theprimary resolution conversion processing portion 34 of the read imagecorrection portion 11 to perform conversion to make the resolution ofthe image data in the main scanning direction be equal to the resolutionof the image data in the sub-scanning direction that is output from theimage reading portion 10.

The primary resolution conversion processing portion 34 converts theresolution of the image data in the main scanning direction into theresolution for outputting the image data to the image writing portion 13such that the resolution in the main scanning direction matches theresolution in the sub-scanning direction, and thus obtained image datais subjected to another image processing and then accumulated once inthe HDD 17.

The image data accumulated in the HDD 17 is sent to the image processingportion 12, and the control unit 21 performs control so as not to causethe secondary resolution conversion processing portion 43 of the imageprocessing portion 12 to perform secondary resolution conversionprocessing. Accordingly, in the secondary resolution conversionprocessing portion 43, the resolution of the image data is converted toa desired resolution in the previous processing, thus the image data issimply caused to pass and is subjected to another data processing in theimage processing portion 12. Thereafter, the image data that is outputfrom the image processing portion 12 is output to the image writingportion 13 via the memory 16, whereby print processing is performed.

By this operation, the time for scanning the document using the imagereading portion 10 can be reduced.

Next is described control processing performed when improving thequality of the read image on the document placed on the document tablein the digital copying machine 1.

First, the image region separation processing performed by the imageregion separation processing portion 30 of the read image correctionportion 11 and filter processing performed by the filter processingportion 32 require matrix ranges of the image, thus the processingability of each of these portions can be exercised by reading the imagedata at high resolution. Also, the accumulated image data can be used toperform two different ways of outputting the image: outputting the imageas a color image onto a paper at the same magnification; and outputtingthe image as a reduced monochrome image onto a paper. In such cases, theimage reading portion 10 and the read image correction portion 11 arecontrolled so that in the image reading portion 10 the image data can beoutput to the device at optimal data characteristics.

In this manner, when improving the read quality of the image of thedocument, the control unit 21 executes the moving speed controlprocessing on the image reading portion 10, and the image readingportion 10 reads, at a normal speed, the speed of the document in thesub-scanning direction, without variably controlling the moving speed.Furthermore, the read image correction portion 11 executes processing onthe portions other than the primary resolution conversion processingportion 34, and the control unit 21 performs control and causes theprimary resolution conversion processing portion 34 of the read imagecorrection portion 11 to not perform conversion on the image data. Thecolor conversion processing portion 33 performs color conversion so asto obtain a predetermined RGB space, and accumulates the image data withsuch image characteristics in the HDD 17.

Thereafter, the control unit 21 performs control to output the imagedata accumulated in the HDD 17 in two different ways. In this case, thesecondary resolution conversion processing portion 43 of the imageprocessing portion 12 is caused to perform conversion so that theresolution of the image data in the main scanning direction becomesequal to the resolution of the image data in the sub-scanning direction,which is obtained when the image data is output from the image readingportion 10. For example, when an instruction is made to output the imagedata accumulated in the HDD 17 to the image writing portion 13 as afirst color output, the compressed image data is extended by theextension processing portion 40 of the image processing portion 12,subjected to filter processing by the filter processing portion 41 inaccordance with the color output, and subjected to color conversion bythe color conversion processing portion 42 in accordance with theplotter characteristics of the image writing portion 13. Specifically,if, for example, the image writing portion 13 is a device for forming animage composed of CMYK, color conversion processing corresponding to thecharacteristics of this device is performed on the image data.

Thereafter, the secondary resolution conversion processing portion 43converts the resolution of the image data to a resolution at which theimage data is output to the image writing portion 13 at the samemagnification. Then, the γ processing portion 44 and the halftoneprocessing portion 45 perform own processing thereof to output theprocessed image data to the image writing portion 13, and the imagewriting portion 13 performs color print processing.

Next, when an instruction is made to output the image data accumulatedin the HDD 17 as a second monochrome output, first the compressed imagedata is extended by the extension processing portion 40 of the imageprocessing portion 12, and subjected to filter processing by the filterprocessing portion 41 in accordance with the monochrome output, and thenthe RGB image data is converted into K data by the color conversionprocessing portion 42.

Thereafter, the secondary resolution conversion processing portion 43converts the resolution of the image data to a resolution at which theimage data is output to the image writing portion 13 at the samemagnification. Then, the γ processing portion 44 and the halftoneprocessing portion 45 perform own processing thereof to output theprocessed image data to the image writing portion 13, and the imagewriting portion 13 performs monochrome print processing.

By this operation, the image reading portion 10 can scan the document athigh quality.

The above has described the two different ways of outputting the imagedata to the image writing portion 13, but the same processing can beperformed when using a plurality of ways of outputting the image data tothe image writing portion 13 and other devices, or when outputting theimage data to each of a plurality of devices.

Next is described processing of distributing the image data to theexternal PC 2 in the digital copying machine 1.

For example, FIG. 4 is used to describe processing of transferring JPEGimage data having a resolution of 300 dpi and composed of RGB to the PC2 via the network. Here, the image reading portion 10 is a devicecapable of reading an image in the main scanning direction of a documentat a resolution of 600 (=m) dpi. There is described processing ofincreasing the speed of reading an image on the document when the imagedata read by the image reading portion 10 is output at a resolution of300 (=n) dpi.

In Step (denoted by “S” in the figure) 1, control of the control unitcauses the image reading portion to make the moving speed of thedocument in the sub-scanning direction be faster than the normal speedso that the image data can be read at a specified resolution of 300 dpi(=p), whereby the image reading portion reads the image at a resolutionof 600 dpi in the main scanning direction of the document and at aresolution of 300 dpi in the sub-scanning direction, and outputs theimage data to the read image correction portion. It should be noted thatwhen using an ADF, the speed at which the image passes through thereading position is made faster than the speed at which the image isread at a resolution of 600 dpi, and the image can be read at 300-dpiresolution in the sub-scanning direction.

In this manner, the reading time can be reduced by increasing the speedof passage.

In Step 2, in the read image correction portion the image regionseparation processing portion extracts a distinctive area of thedocument on the basis of the image data, and outputs the extracted andimage region separation data to the filter processing portion. On theother hand, the scanner γ processing portion performs image γ conversionto convert the γ characteristics of the image reading portion to thecharacteristics to be output, and outputs thus obtained characteristicsto the filter processing portion. The filter processing portion performsprocessing so as to convert the spatial frequencies of the image dataobtained from the scanner γ processing portion. Furthermore, the imageregion separation data obtained from the image region separationprocessing portion is used to perform distinctive filter processing oneach extracted area of the image data.

Moreover, the color conversion processing portion performs colorconversion processing corresponding to the output characteristics on theimage data processed by the filter processing portion. For example, thecolor conversion processing portion converts the image data to universalRGB data and outputs it to the primary resolution conversion processingportion. The primary resolution conversion processing portion performsprimary resolution conversion processing of converting the 600-dpiresolution of the image data in the main scanning direction to aspecified resolution of 300 dpi, reduces the image data to 300×300 dpi,outputs it to the compression processing portion, and outputs the imageregion separation data obtained from the image region separationprocessing portion to the compression processing portion. Thecompression processing portion compresses the image data, which is anoutput from the primary resolution conversion processing portion, into aJPEG format, and compresses the image region separation data obtainedfrom the image region separation processing portion by means of areversible compression processing method.

In Step 3, the image data expansion bus control unit stores andaccumulates the image data in the HDD.

In Step 4, the image data is read from the HDD and sent to the imageprocessing portion. In the image processing portion, the extensionprocessing portion extends the compressed image data and image regionseparation data, the filter processing portion converts the image datainto data characteristics corresponding to the display of the PC, thecolor conversion processing portion converts the color space of the RGBdata obtained when the image data is accumulated into an sRGB space, andthe secondary resolution conversion processing portion is caused by thecontrol of the control unit not to perform resolution conversionprocessing on the image data. Specifically, since the resolution of theimage data is already a resolution desired by the user, i.e., 300 dpi,it is not necessary to operate the secondary resolution conversionprocessing portion. Moreover, the γ processing portion performs γconversion to convert predetermined accumulated image characteristics tothe output characteristics, and the halftone processing portion performsgradation processing in accordance with the characteristics of thedisplay of the PC.

In Step 5, the image data processed by the image processing portion isonce kept in the memory and then output to the PC 2 by a NIC using thenetwork via the external I/F control unit.

The above has described the case in which m=600, p=300, and n=300, butthe same processing can be performed even in the case of other valuesthat can satisfy the relationship of m>p≧n>0.

By this operation, the image reading portion 10 can scan the document athigh quality.

Next, FIG. 5 is used to described processing performed whenfacsimile-transmitting binary image data with a resolution of 200 dpi inthe digital copying machine 1.

Here, the image reading portion 10 is a device capable of reading animage in the main scanning direction of a document at a resolution of600 (=m) dpi. There is described processing of increasing the speed ofreading an image on the document when the image data read by the imagereading portion 10 is output at a resolution of 200 (=n) dpi.

In Step (denoted by “S” in the figure) 11, control of the control unitcauses the image reading portion to make the moving speed of thedocument in the sub-scanning direction be faster than the normal speedso that the image data can be read at a specified resolution of 300 dpi(=q), whereby the image reading portion reads the image at a resolutionof 600 dpi in the main scanning direction of the document and at aresolution of 300 dpi in the sub-scanning direction, and outputs theimage data to the read image correction portion. It should be noted thatwhen using an ADF, the speed at which the image passes through thereading position is made faster than the speed at which the image isread at a resolution of 600 dpi, and the image can be read at 300-dpiresolution in the sub-scanning direction.

In this manner, the reading time can be reduced by increasing the speedof passage.

In Step 12, in the read image correction portion the image regionseparation processing portion extracts a distinctive area of thedocument on the basis of the image data, and outputs the extracted andimage region separation data to the filter processing portion. On theother hand, the scanner γ processing portion performs image γ conversionto convert the γ characteristics of the image reading portion to thecharacteristics to be output, and outputs thus obtained characteristicsto the filter processing portion. The filter processing portion performsprocessing so as to convert the spatial frequencies of the image dataobtained from the scanner γ processing portion. Furthermore, the imageregion separation data obtained from the image region separationprocessing portion is used to perform distinctive filter processing oneach extracted area of the image data.

Moreover, the color conversion processing portion performs colorconversion processing corresponding to the output characteristics on theimage data processed by the filter processing portion. For example, thecolor conversion processing portion converts the image data to universalRGB data and outputs it to the primary resolution conversion processingportion. The primary resolution conversion processing portion performsprimary resolution conversion processing of converting the 600-dpiresolution of the image data in the main scanning direction and 300-dpiresolution of the image data in the sub-scanning direction to aspecified resolution of 200 dpi (=p), reduces the image data to 200×200dpi, and outputs it to the compression processing portion. Thecompression processing portion compresses the image data, which is anoutput from the primary resolution conversion processing portion, into aJPEG format, and compresses the image region separation data obtainedfrom the image region separation processing portion by means of thereversible compression processing method.

In Step 13, the image data expansion bus control unit stores andaccumulates the image data in the HDD.

In Step 14, the image data is read from the HDD and sent to the imageprocessing portion. In the image processing portion, the extensionprocessing portion extends the compressed image data and image regionseparation data, the filter processing portion converts the image datainto data characteristics corresponding to the display of the PC, thecolor conversion processing portion converts the color space of the RGBdata obtained when the image data is accumulated into K data, and thesecondary resolution conversion processing portion is caused by thecontrol of the control unit not to perform resolution conversionprocessing on the image data. Specifically, since the resolution of theimage data is already a resolution desired by the user, i.e., 200 dpi,it is not necessary to operate the secondary resolution conversionprocessing portion. Moreover, the γ processing portion performs γconversion to convert predetermined accumulated image characteristics tothe output characteristics, and the halftone processing portion performsbinarization processing on the image data to convert the image data intobinary data.

In Step 15, the image data processed by the image processing portion isonce kept in the memory and then facsimile-transmitted to a facsimiledevice or PC, which is a pre-specified destination, by the FAX portionusing the communication line via the external I/F control unit.

Here, the resolution of the image data in the sub-scanning directionthat is read by the image reading portion 10 is not 200 dpi but 300 dpi.However, for example, even if reading is performed with priority on thespeed, when the image reading portion 10 itself is not capable ofreading the image data at a resolution of 200 dpi, or when, for example,the ADF cannot sent the document promptly, or when a resolution of 300dpi is required after the processing is performed, or when a resolutionof 300 dpi or higher is required in the image region separationprocessing, it is necessary to read the image data at a resolutioncorresponding to the processability, thus the image data is read at themaximum speed corresponding to the reading ability, while increasing thereading speed.

The above has described the case in which m=600, q=300, p=200, andn=200, but the same processing can be performed even in the case ofother values that can satisfy the relationship of m>q≧p≧n>0.

By this operation, the image reading portion 10 can scan the document athigh quality.

Next is described processing of distributing the image data to theexternal PC 2 and of facsimile-transmitting the image data to theoutside by reading the document once, in the digital copying machine 1.

Here, the image reading portion 10 is a device capable of reading animage in the main scanning direction of a document at a resolution of600 (=m) dpi. There is described processing of outputting the image dataread by the image reading portion 10 to the image writing portion 13 ata resolution of 300 (=n) dpi (color image obtained after 50% reduction),outputting the image data to the PC 2 as monochrome image data having aresolution of 200 (=p) dpi, and increasing the speed of reading an imageon the document when the image data read by the image reading portion 10is output at a resolution of 200 (=n) dpi.

First, the image reading portion 10 and the read image correctionportion 11 read the image data to be output so as to obtain optimalresolutions for these portions. In this example, the image obtainedafter 50% reduction has a larger resolution, thus the image readingportion 10 is caused to perform reading operation so as to obtain aresolution of 300 dpi.

Control of the control unit 21 causes the image reading portion 10 tomake the moving speed of the document in the sub-scanning direction befaster than the normal speed so that the image data can be read at aspecified resolution of 300 dpi (=n), whereby the image reading portion10 reads the image at a resolution of 600 dpi in the main scanningdirection of the document and at a resolution of 300 dpi in thesub-scanning direction, and outputs the image data to the read imagecorrection portion 11.

It should be noted that when using an ADF, the speed at which the imagepasses through the reading position is made faster than the speed atwhich the image is read at a resolution of 600 dpi, and the image can beread at 300-dpi resolution in the sub-scanning direction.

In this manner, the reading time can be reduced by increasing the speedof passage.

In the read image correction portion 11 the image region separationprocessing portion 30 extracts a distinctive area of the document on thebasis of the image data, and outputs the extracted and image regionseparation data to the filter processing portion 32. On the other hand,the scanner γ processing portion 31 performs image γ conversion toconvert the γ characteristics of the image reading portion 10 to thecharacteristics to be output, and outputs thus obtained characteristicsto the filter processing portion 32. The filter processing portion 32performs processing so as to convert the spatial frequencies of theimage data obtained from the scanner γ processing portion 31.Furthermore, the image region separation data obtained from the imageregion separation processing portion 30 is used to perform distinctivefilter processing on each extracted area of the image data.

Moreover, the color conversion processing portion 33 performs colorconversion processing corresponding to the output characteristics on theimage data processed by the filter processing portion. For example, thecolor conversion processing portion converts the image data to universalRGB data and outputs it to the primary resolution conversion processingportion 34. The primary resolution conversion processing portion then iscontrolled by the control unit 21 to output the image data to thecompression processing portion 35 without performing resolutionconversion on the image data. The compression processing portion 35compresses the image data, which is an output from the color conversionprocessing portion, into a JPEG format, and compresses the image regionseparation data obtained from the image region separation processingportion 30 by means of the reversible compression processing method.Then, the image data expansion bus control unit 14 stores andaccumulates the image data into the HDD 17 via the memory 16.

Thereafter, as a first output, the image data accumulated in the HDD 17is first read and sent to the image processing portion 12, and the imageprocessing portion 12 performs image processing on the image data sothat the image writing portion 13 can print the image data, and outputsit to the image writing portion 13. First, the extension processingportion 40 extends the image data, the filter processing portion 41performs filter processing corresponding to a color output to be outputto the image writing portion 13, and the color conversion processingportion 42 performs color conversion corresponding to the plottercharacteristics of the image writing portion 13. For example, if theimage writing portion 13 is a device that forms an image composed ofCMYK, the color conversion processing portion 42 performs colorconversion processing corresponding the characteristics of the imagewriting portion 13.

Then, the control unit 21 performs control such that the secondaryresolution conversion processing portion 43 performs secondaryresolution conversion processing of making the 600-dpi resolution of theimage data in the main scanning direction become equal to the 300-dpiresolution of the image data in the sub-scanning direction. The γprocessing portion 44 and the halftone processing portion 45 perform thesimilar processing to output the image data to the image writing portion13 so that the image data is printed out.

Next, as a second output, the image data accumulated in the HDD 17 isused again, and the image processing portion 12 performs processing ofoutputting the image data to the PC 2 and outputs the image data.

First, the extension processing portion 40 extends the image data, thefilter processing portion 41 then performs filter processingcorresponding to a monochrome output, and the color conversionprocessing portion 42 then converts RGB image data into K data.Thereafter, the secondary resolution conversion processing portion 43performs secondary resolution conversion processing of converting the600-dpi resolution of the image data in the main scanning direction andthe 300-dpi resolution of the image data in the sub-scanning directioninto a resolution of 200 dpi. The γ processing portion 44 and thehalftone processing portion 45 perform the same processing as describedabove and output the image data to the PC 2.

The above has described the case in which m=600, n=300, and p=200, butthe same processing can be performed even in the case of other valuesthat can satisfy the relationship of m≧n>p>0.

Next is described control processing performed for improving the qualityof the image on the document that is read once in the digital copyingmachine 1 when outputting the image to a plurality of devices.

Basically, the resolution at which the reading ability of the imagereading portion 10 can be maximized in the image processing depends onthe reading resolution of a CCD or the like. For example, when the imagereading portion 10 has a line sensor having a resolution of 600 dpi,only image data having a resolution of 600 dpi is obtained even if imageprocessing is performed at 800 dpi by means of computation processing.

Therefore, in order to improve the image quality, the reading resolutionof the image reading portion 10 may be used as it is to read thedocument and accumulate the image data.

FIG. 6 is a flowchart showing processing of printing out read image dataand distributing it to the external PC.

Here, the image reading portion 10 is a device capable of reading animage on the document in the main scanning direction at a resolution of600 (=m) dpi. There is described processing of printing out the imagedata read by the image reading portion 10 at a resolution of 300 (=n)dpi and distributing it to the external PC 2 at a resolution of 200 dpi.

In Step 21, the control unit performs control and causes the imagereading portion to make the moving speed of the document in thesub-scanning direction be faster than the normal speed so that the imagedata can be read at a resolution of 600 dpi (=m), whereby the imagereading portion reads the image at a resolution of 600 dpi in the mainscanning direction of the document and at a resolution of 600 dpi in thesub-scanning direction, and outputs the image data to the read imagecorrection portion.

In Step 22, in the read image correction portion the image regionseparation processing portion extracts a distinctive area of thedocument on the basis of the image data, and outputs the extracted andimage region separation data to the filter processing portion. On theother hand, the scanner γ processing portion performs image γ conversionto convert the γ characteristics of the image reading portion to thecharacteristics to be output, and outputs thus obtained characteristicsto the filter processing portion. The filter processing portion performsprocessing so as to convert the spatial frequencies of the image dataobtained from the scanner γ processing portion. Furthermore, the imageregion separation data obtained from the image region separationprocessing portion is used to perform distinctive filter processing oneach extracted area of the image data.

Moreover, the color conversion processing portion performs colorconversion processing corresponding to the output characteristics on theimage data processed by the filter processing portion. For example, thecolor conversion processing portion converts the image data to universalRGB data and outputs it to the primary resolution conversion processingportion. The primary resolution conversion processing portion then iscontrolled by the control unit to output the image data to thecompression processing portion without performing resolution conversionon the image data, and outputs the image region separation data obtainedfrom the image region separation processing portion to the compressionprocessing portion. The compression processing portion compresses theimage data, which is an output from the primary resolution conversionprocessing portion, into a JPEG format, and compresses the image regionseparation data obtained from the image region separation processingportion by means of the reversible compression processing method.

In Step 23, the image data expansion bus control unit stores the imagedata in the memory, an in Step 24 the image data expansion bus controlunit stores and accumulates the image data stored in the memory into theHDD.

In Step 25, the image data is read from the HDD and sent to the imageprocessing portion. In the image processing portion, the extensionprocessing portion extends the compressed image data and image regionseparation data, the filter processing portion performs filterprocessing corresponding to a color output, and the color conversionprocessing portion performs color conversion corresponding to theplotter characteristics of the image writing portion. For example, ifthe image writing portion 13 is a device that forms an image composed ofCMYK, the color conversion processing portion performs color conversionprocessing corresponding to the characteristics of the image writingportion. Thereafter, in the secondary resolution conversion processingportion, for example, the 600-dpi resolution of the image data in themain scanning direction and the 600-dpi resolution of the image data inthe sub-scanning direction are converted into a CMYK having a resolutionof 300 dpi, in order to perform specified 50% reduced printing, and theγ processing portion and the halftone processing portion perform ownprocessing thereof to output the processed image data to the imagewriting portion.

In Step 26, the image writing portion performs 50% reduced color printprocessing based on the image data that is input from the imageprocessing portion.

On the other hand, in Step 27, the extension processing portion of theimage processing portion extends the compressed image data and imageregion separation data. The filter processing portion converts the imagedata into data characteristics corresponding to the display of the PC.The color conversion processing portion converts the image data to fromthe color space of the RGB data obtained when the image data isaccumulated into the sRGB space. The secondary resolution conversionprocessing portion is controlled by the control unit to convert the600-dpi resolution of the image data in the main scanning direction andthe 600-dpi resolution of the image data in the sub-scanning directionto a resolution of 300 dpi. The γ processing portion and the halftoneprocessing portion perform own processing thereof, whereby the processeddata is output to the image data expansion bus control unit.

In Step 28, the image data is stored in the memory. In Step 29, theimage data is stored and accumulated in the HDD. In Step 30, the imagedata is output to the PC 2 by the NIC using the network via the externalI/F control unit.

In this manner, by reading the image data at a resolution of 600 dpi, animage information amount at which the performance of the image readingportion 10 can be maximized is obtained. Therefore, when performing theimage region separation processing or filter processing as well, resultsof the processing can be obtained more effectively by using the data.

In the digital copying machine 1, the image data read by the imagereading portion is subjected to processing, and is stored once. When thestored image data is subjected to image processing and then output, theprocessing function capable of converting the resolution of the imagedata before or after storing the image data is provided, whereby thereading speed can be increased, the image data processability can beimproved, and the image can be read in two different ways, improving theproductivity of image reading.

Furthermore, even if there are a plurality of devices to which the imagedata read by the image reading portion is output, by reading the imagedata once, the resolution of the image data is converted into aresolution corresponding to the characteristics of each of the devicesto which the image data is output, and then the image data is output tothese devices, thus the image data can be provided to the user whilemaximizing the production capability of image reading without reducingthe productivity of image reading. Also, the reading speed can beincreased as much as possible to provide image data having maximizedprocessability.

Moreover, the resolution conversion function is used in image processingperformed after accumulating the read image data, whereby the scannedimage data can be fully utilized.

The image processing apparatus and image processing method of thepresent invention can be applied to a desktop computer, a laptopcomputer, and other personal computers.

The image processing apparatus and image processing method of thepresent invention can improve the productivity of image reading.

Various modifications will become possible for those skilled in the artafter receiving the teachings of the present disclosure, withoutdeparting from the scope thereof.

1. An image processing apparatus, comprising: reading means for movingthe position of a reading line in a sub-scanning direction of a documentto read an image in a main scanning direction of the document and thento output image data on the read reading line; moving speed controlmeans for variably controlling a speed of the reading means moving inthe sub-scanning direction of the document so that a resolution of theimage data in the sub-scanning direction becomes a specified resolution;first conversion means for converting characteristics of the image dataoutput from the reading means into data characteristics predetermined atthe time of accumulation of the image data; accumulation means foraccumulating the image data converted by the first conversion means;second conversion means for converting the characteristics of the imagedata accumulated by the accumulation means into device characteristicsof a device to which the image data is output; and output means foroutputting the image data converted by the second conversion means tothe device to which the image data is output, wherein the firstconversion means is provided with primary resolution conversion meansfor converting the resolution of the image data in the main scanningdirection or the sub-scanning direction into the specified resolution,and the second conversion means is provided with secondary resolutionconversion means for converting the resolution of the image data in themain scanning direction or the sub-scanning direction into the specifiedresolution.
 2. The image processing apparatus as claimed in claim 1,further comprising control means for performing control so as to, whenincreasing the speed of reading the image on the document, cause themoving speed control means to make the speed of the reading means movingin the sub-scanning direction of the document become faster than anormal speed so as to reduce the resolution of the image data in thesub-scanning direction to the specified resolution by causing thereading means to reduce the number of lines for reading the image data,cause the primary resolution conversion means to perform conversion soas to make the resolution of the image data in the main scanningdirection become equal to the resolution of the image data in thesub-scanning direction, the image data being output from the readingmeans, and cause the secondary resolution conversion means not toperform conversion.
 3. The image processing apparatus as claimed inclaim 1, further comprising control means for, when improving readingquality of the image on the document, performing control so as not tocause the moving speed control means to perform variable control and notto cause the primary resolution conversion means to perform conversion,but to cause the secondary resolution conversion means to performconversion so as to make the resolution of the image data in the mainscanning direction become equal to the resolution of the image data inthe sub-scanning direction, the image data being output from the readingmeans.
 4. The image processing apparatus as claimed in claim 1, whereinthe reading means is means for reading the image in the main scanningdirection of the document at a resolution of m dpi, the image processingapparatus further comprising control means for, when outputting theimage data at a specified resolution of n dpi, causing the moving speedcontrol means to change the speed of the reading means moving in thesub-scanning direction of the document so as to cause the reading meansto read the image data at a specified resolution of p dpi whenincreasing the speed of reading the image on the document, and causingthe primary resolution conversion means to perform conversion so as tomake the resolution m of the image data in the main scanning directionbecome equal to the resolution p dpi of the image data in thesub-scanning direction, the image data being output from the readingmeans, and causing the secondary resolution conversion means not toperform conversion, to perform each of the control (m>p≧n>0).
 5. Theimage processing apparatus as claimed in claim 1, wherein the readingmeans is means for reading the image in the main scanning direction ofthe document at a resolution of m dpi, the image processing apparatusfurther comprising control means for, when outputting the image data ata specified resolution of n dpi, causing the moving speed control meansto change the speed of the reading means moving in the sub-scanningdirection of the document so as to cause the reading means to read theimage data at a specified resolution of q dpi when increasing the speedof reading the image on the document, and causing the primary resolutionconversion means to convert the resolution m dpi of the image data inthe main scanning direction and the resolution q dpi of the image datain the sub-scanning direction into a resolution of p dpi, the image databeing output from the reading means, and causing the secondaryresolution conversion means not to perform conversion, to perform eachof the control (m>q≧p≧n>0).
 6. The image processing apparatus as claimedin claim 1, wherein the reading means is means for reading the image inthe main scanning direction of the document at a resolution of m dpi,the image processing apparatus further comprising control means for,when outputting the image data at two specified resolutions n dpi and pdpi, causing the moving speed control means to change the speed of thereading means moving in the sub-scanning direction of the document so asto cause the reading means to read the image data at a specifiedresolution of n dpi, and causing the primary resolution conversion meansnot to perform conversion, and causing the secondary resolutionconversion means to perform conversion so as to make the resolution m ofthe image data in the main scanning direction become equal to theresolution n dpi of the image data in the sub-scanning direction, theimage data being accumulated in the accumulation means, and to convertthe resolution m dpi of the image data in the main scanning directionand the resolution n dpi of the image data in the sub-scanning directioninto the resolution of p dpi, the image data being accumulated in theaccumulation means, to perform each of the control (m≧n>p>0).
 7. Theimage processing apparatus as claimed in claim 1, wherein the readingmeans is means for reading the image in the main scanning direction ofthe document at a resolution of m dpi, the image processing apparatusfurther comprising control means for, when improving reading quality ofthe image on the document, causing the moving speed control means tochange the speed of the reading means moving in the sub-scanningdirection of the document so as to cause the reading means to read theimage data at a resolution of m dpi (m>0), and causing the primaryresolution conversion means not to perform conversion, and causing thesecondary resolution conversion means to convert the resolution m dpi ofthe image data in the main scanning direction and the resolution m dpiof the image data in the sub-scanning direction into a specifiedresolution, the image data being accumulated in the accumulation means.8. An image processing method, comprising: a reading step of moving theposition of a reading line in a sub-scanning direction of a document toread an image in a main scanning direction of the document and then tooutput image data on the read reading line; a moving speed control stepof variably controlling a speed of moving in the sub-scanning directionof the document so that a resolution of the image data in thesub-scanning direction becomes a specified resolution in the readingstep; a first conversion step of converting characteristics of the imagedata output in the reading step into data characteristics predeterminedat the time of accumulation of the image data; an accumulation step ofaccumulating the image data converted in the first conversion step; asecond conversion step of converting the characteristics of the imagedata accumulated in the accumulation step into device characteristics ofa device to which the image data is output; and an output step ofoutputting the image data converted in the second conversion step to thedevice to which the image data is output; wherein the first conversionstep is provided with a primary resolution conversion step of convertingthe resolution of the image data in the main scanning direction or thesub-scanning direction into the specified resolution, and the secondconversion step is provided with a secondary resolution conversion stepof converting the resolution of the image data in the main scanningdirection or the sub-scanning direction into the specified resolution.9. The image processing method as claimed in claim 8, further comprisinga control step of performing control so as to, when increasing the speedof reading the image on the document, cause the moving speed controlstep to make the moving speed in the sub-scanning direction of thedocument become faster than a normal speed so as to reduce theresolution of the image data in the sub-scanning direction to thespecified resolution by causing the reading step to reduce the number oflines for reading the image data, cause the primary resolutionconversion step to perform conversion so as to make the resolution ofthe image data in the main scanning direction become equal to theresolution of the image data in the sub-scanning direction, the imagedata being output in the reading step, and cause the secondaryresolution conversion step not to perform conversion.
 10. The imageprocessing method as claimed in claim 8, further comprising a controlstep of, when improving reading quality of the image on the document,performing control so as not to cause the moving speed control step toperform variable control and not to cause the primary resolutionconversion step to perform conversion, but to cause the secondaryresolution conversion step to perform conversion so as to make theresolution of the image data in the main scanning direction become equalto the resolution of the image data in the sub-scanning direction, theimage data being output by the reading step.
 11. The image processingmethod as claimed in claim 8, wherein the reading step is a step ofreading the image in the main scanning direction of the document at aresolution of m dpi, the image processing method further comprising acontrol step of, when outputting the image data at a specifiedresolution of n dpi, causing the moving speed control step to change thespeed of moving in the sub-scanning direction the document so as tocause the reading step to read the image data at a specified resolutionof p dpi when increasing the speed of reading the image on the document,and causing the primary resolution conversion step to perform conversionso as to make the resolution m of the image data in the main scanningdirection become equal to the resolution p dpi of the image data in thesub-scanning direction, the image data being output in the reading step,and causing the secondary resolution conversion step not to performconversion, to perform each of the control (m>p≧n>0).
 12. The imageprocessing method as claimed in claim 8, wherein the reading step is astep of reading the image in the main scanning direction of the documentat a resolution of m dpi, the image processing method further comprisinga control step of, when outputting the image data at a specifiedresolution of n dpi, causing the moving speed control step to change thespeed of moving in the sub-scanning direction the document so as tocause the reading step to read the image data at a specified resolutionof q dpi when increasing the speed of reading the image on the document,and causing the primary resolution conversion step to convert theresolution m dpi of the image data in the main scanning direction andthe resolution q dpi of the image data in the sub-scanning directioninto a resolution of p dpi, the image data being output in the readingstep, and causing the secondary resolution conversion step not toperform conversion, to perform each of the control (m>q≧p≧n>0).
 13. Theimage processing method as claimed in claim 8, wherein the reading stepis a step of reading the image in the main scanning direction of thedocument at a resolution of m dpi, the image processing method furthercomprising a control step of, when outputting the image data at twospecified resolutions n dpi and p dpi, causing the moving speed controlstep to change the speed of moving in the sub-scanning direction thedocument so as to cause the reading step to read the image data at aspecified resolution of n dpi, and causing the primary resolutionconversion step not to perform conversion, and causing the secondaryresolution conversion step to perform conversion so as to make theresolution m of the image data in the main scanning direction becomeequal to the resolution n dpi of the image data in the sub-scanningdirection, the image data being accumulated in the accumulation step,and to convert the resolution m dpi of the image data in the mainscanning direction and the resolution n dpi of the image data in thesub-scanning direction into the resolution of p dpi, the image databeing accumulated iny the accumulation step, to perform each of thecontrol (m≧n>p>0).
 14. The image processing method as claimed in claim8, wherein the reading step is a step of reading the image in the mainscanning direction of the document at a resolution of m dpi, the imageprocessing method further comprising a control step of, when improvingreading quality of the image on the document, causing the moving speedcontrol step to change the speed of moving in the sub-scanning directionthe document so as to cause the reading step to read the image data at aresolution of m dpi (m>0), and causing the primary resolution conversionstep not to perform conversion, and causing the secondary resolutionconversion step to convert the resolution m dpi of the image data in themain scanning direction and the resolution m dpi of the image data inthe sub-scanning direction into a specified resolution, the image databeing accumulated by the accumulation step.